what are the uses of kernel recompilalation and how to increase the system performenc

[prasame]

what are the uses of kernel recompilalation and how to increase the system performence

Could anyone suggets me in the below cases:

1)when the application loaded (which consumes more memory)
2) What are the configuration need to set in the "menu config" to increase the performence of the any block device drivers which supports any kind of file systems.

3)when an oracle application loaded usually the syatem performence will come down.What are the configurations to increase the performence.

4) How to increase the storage device performence through menuconfig parameters.

[coopstah13]

What kind of performance problems are you having?

[Rubberman]

Most system performance issues are not a matter of kernel configuration but more an issue of general system configuration, both hardware and software. FWIW, Oracle is a performance hog if only because it generally sucks up a LOT of memory, and it is lack of memory that is the biggest performance bottleneck in any system these days. If you are running a dbms such as Oracle, then you want as much memory as you can stuff into the system, and probably want to be running a 64bit OS as well. For occasional Oracle use, 8GB is generally adequate (what I have on my system) if you are using the system for other general purpose tasks. If you are using it for heavy database use, then you probably want 16-32GB of RAM.

[Xasir]

You can do many things to increase the performance

1) cd to $ORACLE_HOME/rdbms/lib
a) make -f ins_rdbms.mk async_on
b) make -f ins_rdbms.mk ioracle
2) If asynchronous I/O needs to be disabled for some reason,
cd to $ORACLE_HOME/rdbms/lib
a) make -f ins_rdbms.mk async_off
b) make -f ins_rdbms.mk ioracle
3) Parameter settings in init.ora for raw devices:
a) set 'disk_asynch_io=true' (default value is true)
4) Parameter settings in init.ora for filesystem files:
a) Make sure that all Oracle datafiles reside on filesystems that support
asynchronous I/O. (For example, ext2)
b) set 'disk_asynch_io=true' (default value is true)
c) set 'filesystemio_options=asynch'

Follow these steps to lower the SGA base address within Oracle:
· Shutdown all instances of Oracle
· cd $ORACLE_HOME/lib
· cp -a libserver9.a libserver9.a.org (to make a backup copy)
· cd $ORACLE_HOME/bin
· cp -a oracle oracle.org (to make a backup copy)
· cd $ORACLE_HOME/rdbms/lib
· genksms -s 0x15000000 >ksms.s (lower SGA base to 0x15000000)
· make -f ins_rdbms.mk ksms.o (compile in new SGA base address)

These are the linux parameters you can change to increase the performace

. Shutdown the instance of Oracle.

· Open a terminal session (Oracle session).

· Open a second terminal session and su to root (root session).

· Find out the process id for the Oracle session. For example, do
"echo $$" in the Oracle session.

· Now lower the mapped base for the Oracle session to 0x10000000.
From the root session, echo 268435456 >/proc/<pid>/mapped_base,
where <pid> is the process id determined in the earlier step.

· Increase the value of shmmax so that Oracle will allocate the SGA in
one segment. From the root session, echo 3000000000 >/proc/sys/kernel/shmmax

· From the Oracle terminal session, startup the Oracle instance. The SGA
now begins at a lower address, so more of the address space can be
used by Oracle.


May be this can help you but these changes for redhat